mpc853pzt80a Freescale Semiconductor, Inc, mpc853pzt80a Datasheet - Page 57

• Manufacturer Part Number: mpc853pzt80a
• Description: Mpc853t Powerquicc Integrated Communications Processor
• Manufacturer: Freescale Semiconductor, Inc

15 FEC Electrical Characteristics
This section provides the AC electrical specifications for the fast Ethernet controller (FEC). Note that the
timing specifications for the MII signals are independent of system clock frequency (part speed
designation). Also, MII signals use TTL signal levels compatible with devices operating at either 5.0 V or
3.3 V.
15.1
The receiver functions correctly up to a MII_RX_CLK maximum frequency of 25MHz +1%. There is no
minimum frequency requirement. In addition, the processor clock frequency must exceed the
MII_RX_CLK frequency –1%.
Table 25
Figure 59
15.2
The transmitter functions correctly up to a MII_TX_CLK maximum frequency of 25 MHz + 1%. There is
no minimum frequency requirement. In addition, the processor clock frequency must exceed the
MII_TX_CLK frequency – 1%.
Freescale Semiconductor
Num
M1
M2
M3
M4
provides information on the MII receive signal timing.
MII_RXD[3:0] (Inputs)
MII_RXD[3:0], MII_RX_DV, MII_RX_ER to MII_RX_CLK setup
MII_RX_CLK to MII_RXD[3:0], MII_RX_DV, MII_RX_ER hold
MII_RX_CLK pulse width high
MII_RX_CLK pulse width low
MII Receive Signal Timing (MII_RXD[3:0], MII_RX_DV, MII_RX_ER,
MII_RX_CLK)
MII Transmit Signal Timing (MII_TXD[3:0], MII_TX_EN,
MII_TX_ER, MII_TX_CLK)
shows MII receive signal timing.
MII_RX_CLK (Input)
MII_RX_ER
MII_RX_DV
MPC852T PowerQUICC™ Hardware Specifications, Rev. 4
Figure 59. MII Receive Signal Timing Diagram
Characteristic
Table 25. MII Receive Signal Timing
M1
M2
M3
35%
35%
M4
Min
5
5
Max
65%
65%
—
—
FEC Electrical Characteristics
MII_RX_CLK period
MII_RX_CLK period
Unit
ns
ns
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